One night while browsing on my phone, I felt a little horny and decided to look up porn to get more in the mood before bringing myself to orgasm. It took no time. I was wet and achy and in need of a good orgasm. I flipped over on my back and started to massage my pussy. God, I needed this. My husband has been too tired to fuck me for the past several weeks. So I really needed to get off before the sexual frustration became too much. But suddenly, while I was really getting myself closer to coming, I saw my step son peeking through the door watching me. I called out and he retreated down the hall. I then yelled for him to come into my room to scold him for watching me. It turns out he's been watching me in the past. I don't know how, but he always seems to be able to detect when I am going to masturbate. Feeling awkward but still horny, I agree to finish what I started and let him watch while he strokes his cock. My step son has a really nice cock as it turns out. This feeling of him watching me and jacking off was actually turning me on. Thinking about him thrusting his cock in my pussy made me so wet! I came super hard to the thought and so did he. I won't say that it won't happen again. I might even be more bold next time. I just need to make sure he keeps his mouth shut so my husband doesn't find out.